Cutter bit holder



June 11, 1963 s. E. PROCTOR 3,0

CUTTER BIT HOLDER Filed Sept. 29, 1960 2 Sheets-Sheet 1 Fig.1. B

June 11, 1963 s. E. PRocToR 3,093,366

Filed Sept. 29, 1960 2 Sheets$heet 2 United States Patent Ofice3,093,366 Patented June 11, 1963 3,093,366 CUTTER BIT HOLDER SidneyErnest Proctor, High Wycombe, England, assignor to Austin Hoy andCompany Limited, High Wycombe, England, a British company Filed Sept.29, 1960, Ser. No. 59,214 Claims priority, application Great BritainOct. 12, 1959 4 Claims. (Cl. 262-33) This invention comprisesimprovements in or relating to coal-cutter picks.

-It is an object of the invention to provide a quick release device fora coal-cutter pick so that it can be released from the pick box in theshortest possible time.

In coal-cutters as hitherto constructed, a pick is secured in pickboxes, whether in coal-cutter chains or on rotatable pillars or thelike, by means of set screws which enter the pick box from one side andgrip the shank of the pick. To change one pick for another, it isnecessary to unscrew the set screw, loosen the pick shank and remove itand then to insert a new pick shank and screw up the set screw again.Under the conditions in which coal-cutting machines work, especially incases where the picks do not have to be frequently changed, the screwsfrequently become rusted in and are difficult to remove. As there is alarge number of picks on any coal-cutting machine, changing the picksunder these conditions takes a long time and the machine is out of useduring the whole of the time occupied tor changing. Even where thescrews are not rusted much time is wasted while the picks are changedand where corrosion has occurred, the time wasted is increased.

Accordingly the present invention provides a device for retaining acoal-cutter pick by its shank in a socket in a pick-box comprising alatch-member mounted within the shank for movement between a latchedposition in which the-latch-member projects laterally of the shank forengagement with a recess in the wall of the socket and an unlatchedposition in which the latch-member is retracted into the shank, means tourge the latch-member into the latched position and an access boretransverse the axis of the shank whereby access to the latch-member maybe had in order to move it into the unlatched position.

In one construction the access bore traverses the pickbox and intersectsthe recess in the wall of the socket and the insertion of a tommy barinto the access bore releases the pick by engaging the projecting end ofthe latch-member and causing it to retract into the shank.

In a second construction the access bore traverses the head of the pickand the insertion of a tommy bar into the access bore releases the pickby engaging a release member operatively connected to the latch-memberand causing it to retract into the shank. Preferably the re lease-memberis a plunger slidable in the shank of the pick.

Preferably the means to urge the latch into the latched positioncomprise a spring in the bottom of the shankreceiving socket and a plateurged upwardly by the spring into engagement with a tail on thelatch-member.

Embodiments of the device according to the invention will now bedescribed by way of example and with reference to the accompanyingdrawings, in which:

FIGURE 1 is a sectional elevation of a coal-cutter pick retained by itsshank in a socket in a pick-box,

FIGURE 2 is a section on line 2-2 of FIGURE 1,

FIGURE 3 is a sectional elevation of a second coalcutter pick retainedby its shank in a socket in a pickbox,

- FIGURE 4 is a sectional elevation of a third coalcutter pick retainedby its shank in a socket in a pickbox,

FIGURE 5 is a sectional elevation of a fourth coalcutter pick retainedby its shank in a socket in a pickbox,

FIGURE 6 is a sectional elevation of an alternative coal-cutter pick foruse in the construction shown in FIGURE 5', and

FIGURE 7 is a sectional elevation of a fifth coalcutter pick retained byits shank in a socket in a pickbox.

In the construction shown in FIGURES 1 and 2, a pick is provided with ashank 11 to fit a socket 12 in a pickabox 13 and the head 14 of the pickis joined to the shank by a shoulder 15 which, when the pick is home inthe pick-box, rests in a slot 16 cut across the top of the socket.

In the base of the socket there is a plunger 17 beneath which is aspring 18 tending to urge the plunger upwards and the plunger iscapable, if the pick is not held by retaining means in the pick-box, ofejecting it outwards. The spring seats on a plug 19 which closes thebottom of the socket.

The inner end of the shank contains a latch-member 21. The latch-memberis constituted by a short roundended cylindrical plug which is receivedslidably in a hole 22 drilled through the'shank in a direction at 45 toits length in such a position that the lower end of the hole isconcentric with the bottom of the shank and the upper end breaks out ofthe side of the shank part of the way between the bottom end of theshank and the shoulder '15. The latch-member is long enough to projectat one end below the bottom of the shank into engagement with theplunger 17 and at the same time to project at the other end from theside of the shank. A transverse access bore 23 is broached through thepick box at such a position that it cuts partly across the socketprovided for the shank of the pick thus forming a recess in the wall ofthe socket. The upper end of the latchmember where it projects from theside of the shank of the pick, is able to enter into this recess underthe effect of the spring pressure exerted by the plunger and will solock the pick against withdrawal.

If a tornmy-bar is inserted into the side of the pickbox through theaccess bore, it can be used to force the latch-member inwards againstthe action of the spring plunger until the latch-member is retractedinto the shank clear of the recess, whereupon the spring plunger willforce the cutter-pick shank, with the latch-member in it, upwardly outof the pick-box. Thus the pick is automatically ejected as soon as it isreleased.

The tommy-bar for this purpose should be of D-section so that its shankfits the access bore in the pick-box and its flat side engages andreleases the latch-member.

. If desired, the latch-member may have a groove 24 cut around themiddle of its length and a mating groove 25 may be cut in the wall ofthe hole in which the locking member slides. In the latching position,the grooves will register with one another. Around the latch-member inthe grooves there may be a spring ring 26 which tends to centre thelatch-member in the latching position but will yield to allow it to bepushed into the unla-tched position when desired. The spring ring mustbe made weak enough to permit the spring plunger to push thelatch-member into the latching position notwithstanding the friction thering produces.

In the construction shown in FIGURE 3, a cutter-box 31 on a coal-cutterchain is provided with a circular pickshank receiving socket 32 having aflat bottom of somewhat greater depth than the pick-shanks to beemployed. A hole 33 is drilled through the cutter-box into the side ofthe socket at an angle of about 45 downwards and the upper end of thehole is stopped by a screwed plug 34-. Picks are provided havingcircular Shanks 35 and rectangular heads 36. By a rectangular head ismeant rectangular as viewed from along the axis of the pick shank. Theback of each head behind the tip as viewed in side elevation is curvedin the usual way.

A hole 37 is drilled through the pick shank at 45 to its length in aposition in which it will register with the inclined hole 33 in the sideof the socket when the shank is fully home. A second hole 38 parallel tothe hole 37 is drilled in the shank in a position in which it extendsupwardly into the head of the pick and the head is drilled with asomewhat larger access bore 39' which intersects the end of the secondhole 38.

A latch member 41 is provided Which is circular in cross-section and isan easy sliding fit in the hole 37, the upper end of the latch memberbeing cut ofi at such an angle that if it is forced right back in thehole 37 in the shank its end will be flush with the side wall of theshank. It is able however, to slide upwardly and outwardly from thisposition into a position in which it enters the inclined hole 33 in theside of the socket and in the latter position it will serve to lock thepick-shank in place.

A release plunger 42 is provided which fits the hole 38 in thepick-shank and which has a rounded head capable of being pushed into, aposition where it enters the intersecting access bore 39 in thepick-head. The release plunger 42 is rigidly connected to thelatch-member 41 by a cross-bar 43, the plunger, the cross-bar and thelatchmember being made in one piece.

To allow room for the cross-bar to slide in the pickhead the metal at 44between the hole 37 and the hole 38 for the release plunger is removed.Thus, if a tommybar is passed through the access bore in the head of thepick, it will force the release plunger downwardly and make the plungerwithdraw the latch-member.

In the bottom of the socket there is a conical spring 45 which urges alittle plate 46 upwardly against the bottom end of the latch-member 41,which is rounded to receive it. This spring urges the latch-memberupwardly and outwardly into engagement in the hole in the side of thesocket and the tommy-bar, if inserted, will cause the latchmember to beretracted against the spring.

If the pick-shank tends to stick in the socket when the tommy-bar isinserted it is quite easy to rotate the pick by the head of thetommy-bar in the socket and set it free. Undue depression of the releaseplunger by the tommy-bar can be prevented by means of a cross-pin 47which is driven through the shank a little below the position at whichthe release plunger fully withdraws the latch member. Other means, suchas a circlip could be used to retain the latch-member within the pick.

In order to prevent rotation of the pick relatively to the socket whenin use, the rectangular sides of the head of the cutter are employed inconjunction with a recess 48 formed across the mouth of the socket. Therecess is machined just a little wider than the head of the pick andwhen the shank of the pick is pushed into the socket the sides of thehead enter the recess and prevent it turning. The freeing of thecutter-shank by turning it with the tommy-bar is not thereby preventedbecause very slight movement is all which is necessary.

In the construction shown in FIGURE 4, instead of a slidablelatch-member in the shank 51 of the pick, there is a pivoted latch 52which works in a transverse slot 53 machined across the inner end of theshank. This latch 52 has two arms 54 and 55 which are at an angle ofabout 135"; one arm 54 acts as the latch-member and enters a recess 56in the side of the socket 57. The other arm 55, when the latch-member isso entered, extends at right angles to the axis of the shank across thecentre line thereof. In this position it can be engaged by arelease-plunger 58 slidable within the shank coaxially therewith. Asbefore, the head of the release plunger 53 enters a transverse accessbore 59 in the head 61 of the cutter-pick which can be used for theinsertion of a tommy-bar. The quickrelease plunger is held upward by aspring 62 which surrounds it within the shank. There is a further spring63 and cover plate 64 in the bottom of the socket to urge the tail ofthe latch outwardly against the release plunger and to cause the head ofthe latch to snap out into the recess formed in the side of the socket.

As before, the head of the pick fits into a recess cut across the mouthof the socket.

*In the construction shown in FIGURE 5 a cutter-box 71 on a coal-cutterchain is provided With a circular pick-shank receiving socket 72 havinga flat bottom at a somewhat greater depth than the pick-shanks to beemployed. A pick is provided having a circular shank 73 and a pick-head74. A hardened insert 75 is mounted at the cutting edge of thepick-head. The back of the head is curved and has a heel 76 which isreceived in a slot 77 in the pick-box when the shank of the pick isfully entered into the socket; the engagement of the heel and the socketprevents the pick from rotating. Although only one slot 77 is shown inFIGURE 5, other slots may be provided to correspond with other angularpositions of the cutter-pick with respect to the socket. The pickhead isalso formed with a collar 78 which surrounds the pick head except at itsheel; the collar 78 seals the socket 72 when the pick-shank is pushedhome to prevent coaldust from penetrating into the socket.

A bore 81 is drilled through the cutter-box into the side of the socketat an angle of about 45 to the axis of the socket. The bore 81 isdrilled at the rear of the socket, that is to say below the heel.However, other bores may be drilled into the socket to correspond toother angular positions of the cutter-pick with respect to the socket,in particular a corresponding bore may be drilled diametrically oppositeto the bore 81 so that the cutter-pick may be reversed. The lower partof the pickshank is slotted, the slot 82 terminating at an oblique wall83. A bore 84 is drilled through the oblique wall 83 and into thepick-head 74 where it intersects a cross-bore 85; the bore 84 isinclined at an angle of about 45 to the axis of the shank so that it isparallel to the bore 81 in the cutter-box when the shank is received inthe socket.

A latch-member 86 is bent from a metal wire of circular cross-section.The wire is bent into the shape of three sides of a parallelogram; thuswhen the central portion is mounted in the pick-shank parallel to theaxis of the pick-shank, the two end portions are inclined at about 45 tothe axis of the pick-shank so that the upper end portion of thelatch-member enters the bore 84 in which it has an easy sliding fit. Thecentral portion and the lower end portion of the latch-member 86 slideeasily into the slot 82. A cross-pin 87 is secured across the slot 82 sothat the latch-member cannot fall out of the slot. However, thecross-pin does allow the latch-member to slide between two positions;these two positions are a latched position, in which the lower endportion of the latch-member projects from the slot 82 in the shank andin which the upper end portion projects into the crossbore 85 in thepick head 74, and an unlatched position, in which the lower end portionis retracted into the slot 82 and the upper end portion does not projectinto the cross-bore 85. A conical spring 89 is formed with a loop 91 bywhich it is secured to the latch-member 86.

When the pick-shank is pushed home in the socket 72 the spring 89 iscompressed against the bottom of the socket and so urges thelatch-member 86 upwards and mto the latched position. In this latchedposition the lower end portion of the latch-member projects from theslot 82 and enters the bore 81 in the cutter-box, so that the pickcannot be withdrawn from the socket. In order to withdraw the pick atommy-bar is inserted into the cross-bore 85 in the pick head 74. Thisinsertion of the tommy-bar causes the latch-member to move into theunlatched position against the action of the spring 89. In thisunlatched position the lower end portion of the latchmember is retractedfrom the bore 81 into the slot 82, so that the pick-shank can bewithdrawn from the socket.

In practice it is preferred to drill the bore 81 so that it is not quiteparallel to the bore 84 and the end portions of the latch-member. Thusthe bore 81 may be drilled at 50 to the axis of the pick-shank, as shownin broken lines. In this manner a wedging action is obtained between thelatch-member and the bore 81. This wedging action not only serves tosecure the latch-member more firmly in the bore 81 but also tends todraw the pickshank into the socket and so to enable the collar 73 toseal the open end of the socket.

When the pick is cutting coal a turning moment is applied to thepick-head which tends to rotate the pick in a clockwise direction; thismoment is resisted by the heel 76 supported in the slot 77 in thecutter-box. It is an advantage to locate the bore 81 in the rear of thesocket so that no load is imposed on the latch-member 86 due to thecutting pressure on the pick.

Since the conical spring is secured to the latch-member, it is withdrawnfrom the socket with the pick-shank. Thus the latch-member and thespring can both be readily cleaned of any coal-dust which might havepenetrated into the socket.

FIGURE 6 shows an alternative form of pick which can be used in themanner described with reference to FIGURE 5. In FIGURES 5 and 6 likefeatures are referred to by the same reference numerals. Thisalternative pick has a pick head identical with that shown in FIG- URE5. Similarly it is formed with an oblique bore 84 and a cross-bore 85.However, the slot 82 in the lower part of the shank does not passdiametrically across the shank but merely extends a little futher thanthe axis of the shank. The rear portion 92 of the shank remains integralwith the pick. A further oblique bore 93 is drilled through the rearportion 92 at an angle of about 45 to the axis of the shank so as toreceive the lower end portion of the latch-member.

Although the spring means urging the latch-member into the latchedposition in the embodiments described with reference to FIGURES 1 to 6are generally in com pression when the latch-member is in the latchedposition, so as to exert the aforementioned pick-ejecting force when thelatch is withdrawn, it will be noted that the spring means do not haveto exert any force when the latch-member is in its latched position. Thespring means are only required to position the latch-member, which thenprovides a mechanical latch to retain the pick in its cutter-box. Such amechanical latch is not provided by non-mechanical methods of retainingpicks in cutter-boxes, for example methods relying on frictional forces.

FIGURE 7 shows an alternative construction of pick and cutter-box whichis very similar to the construction described with reference to FIGURE6-. However in the construction according to FIGURE 7 a tension spring101 replaces the compression spring 89 shown in FIG URE 5. The tensionspring 101 is secured at one end to a plate 102 at the upper end of theslot 103 formed in the pick-shank. The other end of the tension spring101 is secured to a latch-member 104 which is similar to thelatch-member 86 shown in FIGURE 5. The tension spring 101 urges thelatch-member into its latched position in which it engages a notch 105formed in the Wall of the pick-shank receiving socket.

In order to insert the pick shown in FIGURE 7 into its socket it isnecessary to insert a tommy bar into the cross-bore 106 so as to movethe latch-member into its unlatched position. The pick-shank can then beinserted into the socket and on removal of the tommy bar the pick-shankis latched in position. The pick-shank can be withdrawn from the socketon re-insertion of the tommybar into the cross-bore 106.

In this construction the tension spring 101 can be so arranged as to beunder tension when the latch-member is in its latched position. Undersuch circumstances the spring 101 will have a tendency to pull the pickinto the socket in the cutter-box and will thus ensure that the socketis firmly sealed by the collar 107 on the pickshank, against penetrationof coal-dust into the socket.

It is to be understood that the invention is not limited to the detailsof the foregoing examples; for instance the spring 18 of FIGURE 1 mightbe secured to the plunger 21 in a manner similar to that shown in FIGURE5. Furthermore, although in the foregoing examples the means to urge thelatch-member into the latched position are mechanical springs, it is tobe understood that these Springs could be replaced by other materials ofan elastic nature such as rubber or by any other form of biassing means.Furthermore, although in the foregoing examples the shanks of the cutterpicks are circular, it is to be understood that the shanks could berectangular or may have any other cross-sectional shape.

I claim:

1. In a coal cutter pick and pick box assembly of the class in whichsaid pick is provided with a shank for longitudinal reception andremoval from the socket of a pick box, said pick box normally supportingthe pick with its head projecting from the said socket, the combinationwith said assembly of releasable means for securing the pick in the pickbox comprising a latch member slidably guided through said shank formovement into and from latching reception in a recess in the wall of thesocket, a plunger spaced from said latch member and slidably guided inthe head of the pick for movement parallel to the movement of the latchmember, and means interconnecting said latch member and plunger formovement together, said pick head being formed with a bore therethroughtransversely to said plunger, said plunger projecting partially acrosssaid bore in the latched condition of said latch member.

2. The combination defined in claim 1 including resilient means withinsaid socket urging the latch member toward its latched position.

3. The combination of claim 2 wherein said latch and said plunger areboth guided =for transverse rectilinear movement with respect to saidlongitudinal reception and removal of the pick.

4. The combination as defined in claim 2 in which said plunger has adomed end disposed to project partially across said bore in the latchedcondition of the latch member.

References Cited in the file of this patent UNITED STATES PATENTS2,575,980 Simmons Nov. 20, 1951 2,893,714 Proctor July 7, 1959 2,907,559Brown et a1. Oct. 6, 1959 2,916,275 Bruestle et a1 Dec. 8, -9 2,969,243Drazick Jan. 24, 1961 3,011,794 Vaughn Dec. 5, 1961 3,021,124 Bowen Feb.13, 1962

1. IN A COAL CUTTER PICK AND PICK BOX ASSEMBLY OF THE CLASS IN WHICHSAID PICK IS PROVIDED WITH A SHANK FOR LONGITUDINAL RECEPTION ANDREMOVAL FROM THE SOCKET OF A PICK BOX, SAID PICK BOX NORMALLY SUPPORTINGTHE PICK WITH ITS HEAD PROJECTING FROM THE SAID SOCKET, THE COMBINATIONWITH SAID ASSEMBLY OF RELEASABLE MEANS FOR SECURING THE PICK IN THE PICKBOX COMPRISING A LATCH MEMBER SLIDABLY GUIDED THROUGH SAID SHANK FORMOVEMENT INTO AND FROM LATCHING RECEPTION IN A RECESS IN THE WALL OF THESOCKET, A PLUNGER SPACED FROM SAID LATCH MEMBER AND SLIDABLY GUIDED INTHE HEAD OF THE PICK FOR MOVEMENT PARALLEL TO THE MOVEMENT OF THE LATCHMEMBER, AND MEANS INTERCONNECTING SAID LATCH MEMBER AND PLUNGER FORMOVEMENT TOGETHER, SAID PICK HEAD BEING FORMED WITH A BORE THERETHROUGHTRANSVERSELY TO SAID PLUNGER, SAID PLUNGER PROJECTING PARTIALLY ACROSSSAID BORE IN THE LATCHED CONDITION OF SAID LATCH MEMBER.